The volume is the Proceedings of the Fourth International Congress on Event-Related Potentials of the Brain (EPIC-IV) held in Hendersonville, North Carolina in April 1976. It contains 118 manuscripts including critical reviews and data reports in the following areas of ERP research: (1) electrogenesis and neurochemistry, (2) motor control, (3) information processing, (4) language, (5) developmental disorders, (6) psychopathology, (7) environmental toxicology, (8) scalp distribution, (9) alternatives to signal averaging, and (10) theoretical models. The environmental section assesses the progress of neurobehavioral research on the health effects of environmental toxicants, evaluates the utility of evoked potential research techniques in environmental toxicology, and encourages neurobehavioral research in problems of environmental concern. Many issues concerning the neurochemical substrate and functional significance of ERPs are discussed with the objective of defining multidisciplinary approaches for resolution. The volume provides useful reviews and models to assimilate the growing body of ERP data from anatomy, physiology, pharmacology, psychology, linguistics, toxicology, neurology, psychiatry, and allied clinical sciences. The proceedings will serve, therefore, as a planning document as well as a progress report in the field of ERP research.